Message-ID: <005f01c9cd9b$a9b312c0$0301a8c0@mal769a60aa920>
From: "mal hamilton" <g3kevmal@talktalk.net>
To: <rsgb_lf_group@blacksheep.org>
References: <200904031959.n33Jxrvn028438@smtpa1.mediabeam.com> <BLU146-W15B01E5C9585C664E3CD90CF890@phx.gbl> <20090504220936.59jcwemhlo004wkk@webmail4.kuleuven.be> <01a401c9ccfd$f04e8640$6401a8c0@asus> <20090504233650.cpq3ip6kir688ogo@webmail4.kuleuven.be> <005d01c9cd6b$620ddc00$6401a8c0@asus> <20090505121435.9F59DF3863@smtps02.kuleuven.be> <20090505152548.71C37F3865@smtps02.kuleuven.be>
Date: Tue, 5 May 2009 17:07:59 +0100
MIME-Version: 1.0
Subject: Re: LF: RE: rtty test
Content-Type: text/plain;
	format=flowed;
	charset="iso-8859-1";
	reply-type=original
Content-Transfer-Encoding: 7bit
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org


I think I will stick with CW, the speed is easier to adjust!!
de G3KEV

----- Original Message ----- 
From: "Rik Strobbe" <rik.strobbe@fys.kuleuven.be>
To: <rsgb_lf_group@blacksheep.org>
Sent: Tuesday, May 05, 2009 4:25 PM
Subject: RE: LF: RE: rtty test


> Gary, LF,
>
> I just had a look at MMTTY and it seems pretty easy to set it to 50Hz
> shift and 22Bd baudrate.
> The way I did it:
> 1. As a start select 23Hz RTTY (in "Profiles")
> 2. In "Options" select "Setup MMTTY"
> 3. In the tab "Demodulator" change "Shift" from 23 tot 50 (it is not
> a standard option, but you can just type 50 into the field)
> 4. In the tab "Demodulator" change "Mark" to a suitable value (that
> is the audio frequency you get)
> 5. In the tab "Demodulator" change "Discriminator Type" from VCO to FIR 
> BPF
> 6. In the tab "Demodulator" change "Tap" from 72 to 256
> 7. In the tab "Demodulator" click on "OK"
> 8. In the tab "Decode" change "BaudRate" from 45 tot 22 and click "OK"
> Steps 5-7 set demodulator type, the values above are the result of
> some brief dry tests and can most likely still be optimized. You can
> do that in the main screen.
>
> If WX permits (no rain) I intend to run some tests between 20:30 and
> 21:30 UTC on 503.5kHz in mode USB (so if you listen in LSB don't
> forget to select reverse mode).
> I will announce the exact hours later this evening.
> Between transmissions I will listen on the same frequency.
>
> All reports (or replies) are welcome.
>
> 73, Rik  ON7YD - OR7T
>
> At 14:14 5/05/2009, you wrote:
>>Hello Gary,
>>
>>I had a closer look at the 23Hz shift option of MMTTY and it seems
>>to run at 45Bd what is on the edge regarding the shift/baudrate
>>ratio. That is most likely the reason why it is not so robust.
>>Using 45Bd at 85Hz shift would exceed the 100Hz bandwidth limit.
>>I guess the best option for RTTY would be a shift around 50Hz and a
>>lower baudrate (say 20Bd) what would well fit within the 100Hz
>>bandwidth and would have a sufficient shift/baudrate ratio to
>>provide a robust signal.
>>I will see if I can get such signal out of MMTTY and - if time
>>permits - run some tests tonight.
>>
>>73, Rik  ON7YD - OR7T
>>
>>At 12:22 5/05/2009, you wrote:
>>>Hi Rik,
>>>
>>>You have experienced the same as I did with 23Hz shift, the signal needs 
>>>to
>>>be very strong to decode. It was in the last 2 minutes that I got the
>>>partial decode.
>>>
>>>A much better shift to use is the 85Hz which will fit into your spec.
>>>
>>>I have had good QSO's with Chris G3XIZ in Biggleswade both of us using 
>>>85Hz.
>>>
>>>Give that a try next time & I believe I will get a much better decode
>>>judging by the strength of your signal.
>>>
>>>73
>>>
>>>Gary - G4WGT.
>>>
>>>-----Original Message-----
>>>From: owner-rsgb_lf_group@blacksheep.org
>>>[mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Rik Strobbe
>>>Sent: 04 May 2009 22:37
>>>To: rsgb_lf_group@blacksheep.org
>>>Subject: Re: LF: RE: rtty test
>>>
>>>Hello Gary,
>>>
>>>call the is almost right, locator completely.
>>>But not really impressive for 500mW ERP.
>>>I could see my signal on your grabber, some slow QSB but strong for
>>>the last 2 minutes or so.
>>>I used MTTY with the profile "23Hz RTTY (MTTY)" without any further
>>>changes, not sure that this is the best mode.
>>>So any advice is welcome.
>>>I have also installed MultiPSK, but am still overwhelmed by the colors
>>>and options.
>>>I am allowed to use any digital mode as long as I stick to max. 100Hz
>>>bandwidth.
>>>
>>>73, Rik  ON7YD - OR7T
>>>
>>>
>>>
>>>Quoting Gary - G4WGT <g4wgt@tiscali.co.uk>:
>>>
>>> > Hi Rik,
>>> >
>>> > This is the best I could do, it looks like almost your call sign & 
>>> > locator
>>> > :-
>>> >
>>> > RHTQHTST DE TC(TIOJ7T OR1T JO20IX
>>> >
>>> > 73
>>> >
>>> > Gary - G4WGT.
>>> >
>>> > -----Original Message-----
>>> > From: owner-rsgb_lf_group@blacksheep.org
>>> > [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Rik Strobbe
>>> > Sent: 04 May 2009 21:10
>>> > To: rsgb_lf_group@blacksheep.org
>>> > Subject: LF: rtty test
>>> >
>>> > dear all,
>>> >
>>> > I will run a short (10 minute) rtty test (23Hz shift) on 503.500 at 
>>> > 21UTC
>>> > Reports and/or reply welcome.
>>> >
>>> > 73, Rik  ON7YD - OR7T
>>> >
>>> >
>>> >
>>
>
>


--------------------------------------------------------------------------------



No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 8.0.238 / Virus Database: 270.12.18/2096 - Release Date: 05/04/09 
17:51:00